Monomolecularly thin fluid film

Figure 1 Diagrammatic representation of the ultrastructure of the respiratory membrane. Arrows indicate the passage of drugs (horizontal heavy lines) through the respiratory membrane after alveolar or capillary exposure, or of metabolites (horizontal broken lines) generated in the epithelial or endothelial layers. Key (1) monomolecular surfactant layers, (2) thin fluid film, (3) interstitial space, (4) endothelial capillary basement membrane, (5) drug transport from the alveoli, (6) absorption of drug into endothelial cells from the circulation, (7) transport of drug from the circulation to alveolar epithelium, (8) transport of drug from the circulation to the alveoli. (From Ref. 102. Reproduced by permission, CRC Press, Inc.)...

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